Fig. 6

Evaluation of the effects of hydroxytyrosol on cell cycle and radiation-induced γH2AX formation and apoptosis in human keratinocytes. Cells were treated with the indicated concentrations of hydroxytyrosol for 24 h prior to cell cycle analysis (a). In separate experiments, untreated or cells treated with the indicated concentrations of hydroxytyrosol for 24 h were irradiated with 2 Gy. Cells were then fixed and stained for DNA double-strand breaks using γH2AX foci as molecular markers (b). In another series of experiments, untreated or cells treated with 20 mM hydroxytyrosol for 24 h were irradiated with indicated doses. Cells were then washed and incubated for a further 24 h prior to analysis for apoptosis by monitoring induction of caspases 3 and 7 (c). Means ± standard deviations of survival from a representative of at least two independent experiments are shown; **P < 0.01; *** and ^### P < 0.001